import math
x1,y1,x2,y2=map(float,input().split())
dx,dy=x2-x1,y2-y1
d=math.sqrt(dx*dx+dy*dy)
print("{:.8f}".format(d)) import math math x1,y1,x2,y2=map(float,input().split()) x1 map(float,input().split()) map float input().split() ().split () input split y1 x2 y2 dx,dy=x2-x1,y2-y1 dx x2-x1 x2 x1 dy y2-y1 y2 y1 d=math.sqrt(dx*dx+dy*dy) d math.sqrt(dx*dx+dy*dy) math.sqrt math sqrt dx*dx+dy*dy dx*dx dx dx dy*dy dy dy print("{:.8f}".format(d)) print "{:.8f}".format(d) "{:.8f}".format "{:.8f}" format d x1,y1,x2,y2=map(float,input().split()) map(float,input().split()) x1 x2,y2=map(float,input().split()) map(float,input().split()) x2 dy=x2-x1,y2-y1 y2-y1 dy dx,dy=x2-x1,y2-y1 x2-x1 dx d=math.sqrt(dx*dx+dy*dy) math.sqrt(dx*dx+dy*dy) d y1,x2,y2=map(float,input().split()) map(float,input().split()) y1 y2=map(float,input().split()) map(float,input().split()) y2
import math
x1,y1,x2,y2=map(float,input().split())
dx,dy=x2-x1,y2-y1
d=math.sqrt(dx*dx+dy*dy)
print("{:.8f}".format(d))
